Inspection Procedure

1. Disconnect the A19 ECU.
Fig 1: Identifying A19 ECU Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the wire harness side connector.

   Standard resistance 

   TESTER CONNECTION AND SPECIFIED CONDITION
   
   

   Tester Connection	Switch Condition	Specified Condition
   A19-28 (HDCS) - Body ground	Downhill assist control switch is not pushed	10 kΩ or higher

OK: REPLACE ABS AND TRACTION ACTUATOR ASSEMBLY 

NG: Go to next step. 

1. Remove the downhill assist control switch.
Fig 2: Identifying Downhill Assist Control Switch
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the resistance of the switch.

   Standard resistance 

   TESTER CONNECTION AND SPECIFIED CONDITION
   
   

   Tester Connection	Switch Condition	Specified Condition
   4 - 1	Switch is pushed	Below 1 Ω
   4 - 1	Switch is not pushed	10 kΩ or higher

NG: REPLACE DOWNHILL ASSIST CONTROL SWITCH 

OK: Go to next step. 

1. Disconnect the A19 ECU connector.
Fig 3: Identifying A19 ECU And E31 Switch Connectors Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Disconnect the E31 switch connector.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance 

   TESTER CONNECTION AND SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A19-28 (HDCS) - E31-4	Below 1 Ω
   A19-28 (HDCS) - Body ground	10 kΩ or higher
   E31-1 - Body ground	Below 1 Ω

NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

OK: REPLACE ABS AND TRACTION ACTUATOR ASSEMBLY